• Education of Primary School Mathematics
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• v.23 no.3
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• pp.117-134
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• 2020

Based on the current curriculum, students learn the concept of fraction in the 3rd grade for the first time. At that time, fraction is introduced as whole-part relationship. But as the idea of fraction expands to improper fraction and so on, fraction as measurement would be naturally appeared. In that situation where fraction as whole-part relationship and fraction as measurement are dealt together, it is necessary for students to get experiences of understanding and exploring unit and whole adequately in order to fully understand the concept of fractions. Therefore, the purpose of this study is to analyze how to deal with unit fractions, how to implement activities to find the standard of reference from the part, and what visual representations were used to help students to understand the concept of fractions in elementary mathematics textbooks from the 7th to the 2015 revised curriculum. And we analyzed 60 3rd graders' understanding of finding and drawing the whole by looking at the part. Several didactical implications for teaching the concept of fractions were derived from the discussion according to the analysis results.

• Education of Primary School Mathematics
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• v.23 no.4
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• pp.191-206
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• 2020

The purpose of this study was to find an implication for a direction to improve professional development in mathematics by exploring elementary school teachers' perception of the need for professional development in mathematics. To this end, 4 elementary school teachers were organized into one focus group, and group discussion materials were collected and analyzed based on cases of mathematics professional development needs. As a result of the study, the elementary school teachers' perception that the need for professional development in mathematics is both unnecessary and necessary. The perception of unnecessary was influenced by the easy level of elementary school mathematics content and the ease of teaching. Also, the perception of necessary factors were considering various aspects of mathematics teaching, changing the accumulation of failures in mathematics classes, maintaining authority of students, demand for class improvement due to social change, the impact of school work, the influence of the community of professional development and peers in school, and efforts to grow as teachers. Based on these results, the author discussed ways to promote teachers' participation in mathematics professional development by considering elementary school teachers' perceptions of the need of mathematics professional development.

• Journal of Educational Research in Mathematics
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• v.21 no.4
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• pp.361-378
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• 2011

Since textbooks are developed according to the curriculum, it might be said that the terms registered in curriculum can serve as guidelines for terms used in textbooks. But it really is not. In this study, so that terms registered in curriculum can serve as guidelines for terms used in textbooks, inconsistencies between them would be found out and improved. To this end, suitability of selecting and using terms are discussed, focusing on terms registered in curriculum and terms used in textbooks. In fact, there are significant differences between the terms registered in curriculum and the terms in textbooks, because there is not any criteria in selecting and using terms. In this study the five criteria with respect to registering terms in curriculum are proposed. Everyday language should not be registered. Naturalized terms should not be registered. Terms used in only elementary mathematics, but are already well-established should be registered. Same term used in diverse context should be registered only once. Terms which can be used without definition should be designated. Three criteria in regard to using terms in textbooks are proposed. Terms registered in curriculum must be used. Same term used in diverse context should be redefined in every context. Terms that are not certified and are not absolutely necessary must not be used.

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.2
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• pp.259-281
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• 2016

Teaching practicum plays a significant role in teacher education program because it provides pre-service teachers with an opportunity to apply what they have learned to the actual teaching contexts. As such, it needs to be conducted in terms of close collaboration between university and school. Given that, in a mathematics methods course the prospective teachers in this study had an opportunity to discuss mathematics lessons they had implemented during their teaching practicum. This paper analyzed in what ways prospective teachers' comments on elementary mathematics instruction were changed through this experience. The results of this study showed that in late comment the teachers tended to focus more on mathematical discourse, consider not only the teacher of the lesson but also students, and suggest alternative approaches on the classroom events they had noticed. It is noticeable that the results analyzed by researchers were consistent with prospective teachers' self-assessment. Building on these results, this paper provides implications of teacher preparation programs to enhance prospective teachers' ability to analyze elementary mathematics lessons.

• Journal of Educational Research in Mathematics
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• v.9 no.1
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• pp.263-278
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• 1999

Computer with various powerful functions has profound potential for mathematics instruction and learning. As computer technology progress, its applicability to mathematics education become more comprehensive. Not only its functional development but various psychological positions also changed the way computer technology utilized in mathematics education. In behaviorist's perspective, computer viewed as a teaching machine and constructivist viewed computer as microworld where students could explore various mathematical contents. Both theoretical positions emphasized individual aspect of learning because behaviorist tried to individualize learning using computer and constructivist focused on the process of individual construction. But learning is not only a individual event but also a social event. Therefore we must take social aspect into account. This is especially important when it comes to computer based learning. So far, mathematics loaming with computer weighed individual aspect of loaming. Even in microworld environment, learning should be mediated by teacher and collaborative learning activities. In this aspect, the roles of teacher and peers are very important and socio-cultural perspective sheds light on the computer based learning. In socio-cultural perspective, the idea of scaffold is very important in learning and students gradually internalize the social dimension and scaffolding is gradually faded. And in the zone of proximal development, teacher and more competent peers guide students to formulate their own understanding. In sum, we must take following points into account. First of all, computer should not be viewed as a medium for individualized teaming. That is, interaction with computer should be catalyst for collaborative activities with peers. So, exploration in computer environment has to be followed by small group activities including small group discussion. Secondly, regardless of the role that computer would play, teacher should play a crucial role in computer based learning. This does not mean teacher should direct every steps in learning process. Teacher's intervention should help student construct actively. Thirdly, it is needed to conceptualize computer in learning situation as medium. This would affect learning situation and result in the change of pre-service and in-service teacher training. Computer to be used effectively in mathematics classroom, researches on assessment of computer based learning are needed.

• School Mathematics
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• v.1 no.2
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• pp.637-660
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• 1999

Although ‘to understand mathematics’ is an important educational purpose, most student do not have a relational understanding of the basic concept of mathematics but have a instrumental understanding. This paper will investigate the possibility of using computers for enhancing relational understanding. In the ‘Qualitative case study’, three students who are in the first grade at E-High school took part in 7 activities during four weeks, and were later interviewed and engaged in informal discussion and were observed. This is the result of this study. 1. The three students were passive participants in mathematics problem solving situation at school. Therefore, student B just applied formulas which she had memorized, and student C would forgot the formulas occasionally. These common students needed to participate actively in doing mathematics. 2. The activities utilized two software healing with connection between graphs and function, giving the students the opportunity to plan, practice, and test by themselves. As a result, they understood the mathematical formulas and rules more deeply through their own trial and error, and then they gained thinking abilities necessary for doing mathematics. In addition, the activities boosted their confidence. 3. The understanding type of students was slightly different. Student A who received a high score, understood the most relationally, but student B who received a very high score, understood instrumentally and so couldn't app1y her knowledge to solving problems related to function concept. Student C who received a middle score lacked knowledge of mathematics but thought more creatively. The result is that students need an opportunity to think rotationally regardless of score. Therefore, this study concludes that using computer software will provide a positive effect for relational understanding in loaming function concept.

• Journal of Radiation Protection and Research
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• v.42 no.2
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• pp.130-140
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• 2017

Background: With the need for a domestic level 3 probabilistic safety assessment (PSA), it is essential to develop a Korea-specific code. Health effect assessments study radiation-induced impacts; in particular, long-term health effects are evaluated in terms of cancer risk. The objective of this study was to analyze the latest cancer risk models developed by foreign organizations and to compare the methodology of how they were developed. This paper also provides suggestions regarding the development of Korean cancer risk models. Materials and Methods: A review of cancer risk models was carried out targeting the latest models: the NUREG model (1993), the BEIR VII model (2006), the UNSCEAR model (2006), the ICRP 103 model (2007), and the U.S. EPA model (2011). The methodology of how each model was developed is explained, and the cancer sites, dose and dose rate effectiveness factor (DDREF) and mathematical models are also described in the sections presenting differences among the models. Results and Discussion: The NUREG model was developed by assuming that the risk was proportional to the risk coefficient and dose, while the BEIR VII, UNSCEAR, ICRP, and U.S. EPA models were derived from epidemiological data, principally from Japanese atomic bomb survivors. The risk coefficient does not consider individual characteristics, as the values were calculated in terms of population-averaged cancer risk per unit dose. However, the models derived by epidemiological data are a function of sex, exposure age, and attained age of the exposed individual. Moreover, the methodologies can be used to apply the latest epidemiological data. Therefore, methodologies using epidemiological data should be considered first for developing a Korean cancer risk model, and the cancer sites and DDREF should also be determined based on Korea-specific studies.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.249-273
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• 2004

Finding an optimal solution in MADN[(Multi-Attribute Decision-Making) problems is difficult, when the number of alternatives, or that of attributes is relatively large Most of the existing mathematical approaches arrive at a final solution on the basis of many unrealistic assumptions, without reflecting the decision-maker's preference structure exactly. In this paper we suggest a model that helps us find a group consensus without assessing these parameters in specific cardinal values. Therefore, This research provides a comprehensive Decision Making of the theory and methods applicable to the analysis of decisions that involve risk and multiple criteria attributes. after, The emphasis of the procedure will be on developments from the fields of decisions analysis and utility theory of Taguchi Method. This theoretical development will be illustrated through the discussion of several real-world application and a case study. When the multiple number of decision makers are involved in the decision making procedure, the problem of uncertainties invariably occurs, because of the different views between them. In this paper, New decision making model using Taguchi Method is applied to effectively model the multi-attribute-decision making(MADM) procedure in the uncertainties dominated two area(quantitative and qualitative factors), Quantitative factors evaluation is used Loss Function of Taguchi, qualitative factors evaluation is used 50 ratio by each specialist. thus it can be used for aiding of preferable alternative. as a result, We will be proved efficiency about New decision making model of applied Taguchi Method with Analytical presentation of all the expecting outcomes when a specific strategy or an alternative plan is selected under expecting future environment.

• Geophysics and Geophysical Exploration
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• v.23 no.2
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• pp.89-96
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• 2020

This tutorial summarizes the coordinate transforms for formulating geophysical problems. To ensure mathematical consistency, this discussion begins with the right-hand rule. Further, the concepts of active and passive transforms are introduced. By extending these concepts, the coordinate transform and its inverse between two coordinates are related to the matrix transpose. The yaw-pitch-roll rotation and the azimuth-deviation-tool face rotation transforms are described as the most frequently used schemes, and the relation between the Rodrigues' rotation formula and these two transforms are mathematically explained. The "Gimbal Lock" problem inherent in yaw-pitch-roll rotation is schematically presented and mathematically derived. As a useful tool overcome this problem, the principle and usage of the quaternion is also described.

• Education of Primary School Mathematics
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• v.18 no.2
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• pp.77-89
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• 2015

In this study, an 'Independent Study Checklist' for gifted mathematics students was developed and applied. The characteristics shown in the results after the 'Independent Study Checklist' was applied to mathematics gifted students were analysed. The checklist was divided into six phases of the independent study process and included checking contents at each stage. Observations, student interviews and results of the process of 'Independent Study' were collected and analysed to understand the characteristics of students' outcomes. The results from the application of the 'Independent Study Checklist' suggest the followings. First, the 'Independent Study Checklist' took the role of a self-check list to identify the process of the 'Independent Study'. Second, the check points of the 'Independent Study Checklist' presented the view of discussion to gifted students. Third, the 'Independent Study Checklist' was used as teaching material for teachers of gifted students. Fourth, 'Independent Study Checklist' was optionally used according student's study topics and method. Fifth, the checklist at each phase was continuously used during the whole process of 'Independent Study'. The teachers' interest and encouragement took the role of facilitating students' study process.